1. Field of the Invention
The present invention relates in general to a displaying apparatus with a flat panel, and more particularly, to a displaying apparatus with a flat panel having a ground structure of a printed circuit board (PCB) being improved.
2. Description of the Background Art
A flat panel displaying apparatus generally includes a front cover having a central opening, a rear cover closely coupled to the front cover, and a liquid crystal display (LCD) panel provided between the front cover and the rear cover, being connected to an external system so as to display a picture.
A liquid crystal display panel includes a plate-shaped liquid crystal display module displaying a picture outwardly, and a chassis defining an external appearance of the displaying apparatus. On the lower part of the liquid crystal display module, there is provided a lamp illuminating the liquid crystal display module. To the rear of the liquid crystal display module, there is mounted a printed circuit board driving the liquid crystal display module.
The printed circuit board is constructed by stacking a plurality of substrates formed with circuits in layers. In a lower edge of the printed circuit board, there is provided a connector coupled to a connection cable allowing the connector to be connected to an external system. A liquid crystal display controller is connected to the connector, so as to activate the liquid crystal display module according to signals inputted from the external system. In the upper edge portion of the printed circuit board are provided a plurality of driver integrated circuits (IC), converting the digital signals from the liquid crystal display controller into analog signals so as to display a picture on the liquid crystal display module. The driver integrated circuits are assembled to the liquid crystal display module. The liquid crystal display controller and the driver integrated circuits are connected together by a plurality of signal lines provided in the printed circuit board. The signal lines transmit the digital signals from the liquid crystal display controller to the respective driver integrated circuits.
Recently, there is a growing tendency to miniaturize flat panel displaying apparatus in weight and dimension. To comply with this tendency, the printed circuit board has been steadily decreasing in size. As the size of the printed circuit board becomes small in comparison to the number of the signal lines interconnecting the liquid crystal display controller and the driver integrated circuits, the ground portions of the printed circuit board are dispersed. The ground portions formed on the respective substrates are interconnected through holes.
Some of the ground portions of the printed circuit board are connected to a pair of conductor plates that are coupled to opposite sides of the chassis by screws, thereby allowing the printed circuit board to be grounded to the chassis.
In the earlier flat panel displaying apparatus, only some of the ground portions of the printed circuit board are coupled to the sides of the chassis, in view of the structure of the printed circuit board. However, because no ground portion is formed around the liquid crystal display controller, the place that emits electromagnetic waves the most intensely over the flat panel displaying apparatus, emission of the electromagnetic waves increases. As a result, the digital signals transferred through the signal lines between the liquid crystal display controller and the driver integrated circuits become unstable due to the electromagnetic waves, thereby lowering a reliability of the product.
Exemplars of the art are U.S. Pat. No. 6,175,396 B1 by Kim et al., for Liquid Crystal Display Module, U.S. Pat. No. 5,986,737 by Evanicky et al., for Multi-layer Flat Panel Display Screen Apparatus, U.S. Pat. No. 5,796,578 by Jones, for RF Grounding And Heat Distribution System for a Portable Computer Including a Slip Joint Hinge with a Banana Plug Type Male Intrusion Member, U.S. Pat. No. 5,138,565 by Satou, for Shielded Electronic Apparatus Having a Removable Shielded Display, Japanese Patent No. 6-37478 by Kubo et al., for Driving Apparatus for Liquid Crystal, Japanese Patent No. 9-146109 by Iwami, for Liquid Crystal Display Device, Japanese Patent No. 10-10565 by Yamashita, for Liquid Crystal Display Device And Electronic Equipment, Japanese Patent No. 10-74550 by Watanabe, for Equipment with Connector And Liquid Crystal Display Device, Japanese Patent No. 10-177881 by Page Jr., for HF Noise Screened Electric Connector Arrangement e.g. for Medical/Surgical Video Camera, Japanese Patent No. 10-340759 by Leonard et al., for Shielded Electrical Connector, and Japanese Patent No. 11-284291 by Tashiro, for Circuit Board And Liquid Crystal Display Device with the Circuit Board Mounted.